138 - REPTILES AND BIRDS. 
THE ALLIGATORIDE 
Include the Jacares, Alligators, and Caimans. 
The /Jacares have the head oblong and depressed, with a ridge 
across the face in front of the eyes; teeth unequal, canines of the 
lower jaw fitting into a pit in the upper jaw; toes only partially 
webbed, eyelids fleshy, nostrils separated by a cartilage. Five 
species are described—namely, /. /ssifes, from tropical America, 
six feet in length; /. sclerops, from the Brazils; /. wzgra, also from 
the Brazils; /, punctulatus, with triangular oblong head, muzzle 
elongated, thin and flat, with a rounded point in front, and a slight 
enlargement behind the nostrils ;_/. vad/efrons, differing slightly from 
the above—both natives of the Brazils. 
Alligators have the jaws oblong, much depressed, broad and 
nearly parallel; forehead with a small longitudinal ridge between 
the orbits; feet fringed, toes half webbed, the outer toes free ; 
nostrils separated by a bony septum rising from the upper edge, 
muzzle lengthening with age. The species best known is Ad/igator 
mississipensts, which is a native of North America; its average 
length is six to seven feet, although Bartram informs us that in 
Florida it has been found twenty-three feet long. 4. Aalgebrosus, 
A. sclerops, A. punctulatus, and A. cynocephalus are natives of South 
America; and A. /ucius is found in the southern portion of North 
America. 
The Caimans have the jaws oblong, depressed, rounded, and 
swollen at the end, without frontal ridges or maxillary pits ; teeth 
unequal, the lower canines fitting into pits in the upper jaw; toes 
webbed. There are several species described—C. ¢rigonatus, C. 
palpebrosus, and C. goddeceps, all natives of tropical America. 
C. acutus is also found in Martinique and San Domingo; C. 
rhombifor, 11 Cuba. 
The principal characteristics of the Alligatoride are a head one- 
third the length, a very short muzzle ; teeth unequal in shape and 
size, the fourth lower tooth buried into the upper jaw when the 
mouth is closed; the first teeth of the lower jaw piercing the upper 
at a certain age, so as to appear through the muzzle when closed ; 
the hinder legs and feet rounded, having neither crest nor indenta- 
tion on their edges ; the intervals of the toes more than half covered 
with a short membrane, forming semi-palmated feet. 
It is generally adinitted, as we have stated above, that there 
are six species of this genera, all American, the type of which 
